<!DOCTYPE html>
<html>
<head>
  <meta http-equiv="content-type" content="text/html; charset=us-ascii">
</head>
<body>
  <iframe width="400" height="400" src="data:application/xhtml+xml;charset=us-ascii,<html xmlns='http://www.w3.org/1999/xhtml'><h1>Test</h1></html>"></iframe>
</body>
</html>
